In a record/playback device for magnetic recording of manual drive type, a magnetic card is provided with a timing signal area as well a record/playback area.
And in said record/playback device the magnetic card path faces a read-out/write-in magnetic head as well as a read-out magnetic head. In recording and playback, said read-out/write-in head slides in contact with said record/playback area, while said read-out head slides in contact with said timing signal area. Thus, in response to a clock pulse given from said read-out magnetic head, said read-out/write-in head records or plays back information in the record/playback area of the magnetic card.
Therefore in such a device, said read-out/write-in device becomes structurally complicated and at the same time its control circuit becomes unavoidably complicated.
Meanwhile, for the purpose of preventing erroneouscancelling of record, a microswitch or a photosensor which detects a notch provided at a specific position of a magnetic card is installed in the magnetic card path of the record/playback device. When a notched card comes into the magnetic card path, said microswitch or photosensor detects the notch and thereupon an electric signal issued from said microswitch or photosensor causes supply of an electric current for write-in to the magnetic head to be stopped.
Such an anti-cancel system, calling for a control circuit as well as for a notch-sensing means like a microswitch or a photosensor, naturally has a complicated structure.
Moreover, a magnetic card can freely pass over the magnetic head in the magnetic card path even when a write-in stop signal is being issued from the notch-sensing means; therefore if for some cause the magnetic head happens to be in a write-in mode, the magnetic card passing over the head is likely to be written in.